This study aims to assess the estimated values of evapotranspiration using the surface energy balance system (SEBS model) and four climatic models widely used including Penman-Monteith (FAO 56-PM), Penman (FAO 24-P), radiation (R) and Hargreaves-Samani (HS). Remote sensing model (SEBS) was used to estimate daily actual evapotranspiration values for wheat, Sugar beet and green onions crops using nine Landsat ETM+7 satellite images representing the 2012 / 2013season. The selected site represents a private farm (6^th October agricultural company) located in Ismailia governorate (between 31.92 and 32.62 E longitudes and 30.38 and 30.52 N latitudes). Results indicated that there were clear differences between the estimated Et_a values using any of the tested climatic or remote sensing models. The Et_a values estimated by SEBS, P, R, and HS methods were lower than those estimated by PM method. Estimated Et_a values using SEBS model were generally low compared with those estimated by the tested climatic models. The actual evapotranspiration values (Et_a) for the studied crops using SEBS, PM, P, R, and HS methods are 384, 574, 382, 450, and 329 for wheat, 491, 533, 331, 409 and 264 for sugar beet and 279, 614, 414, 508 and 360 mm/season for green onion crop respectively. Data suggested that, more studies and verification are needed to evaluate all the factors that might affect the quality of data affecting the surface energy balance under arid lands condition. Results concluded also that more verification through several consecutive seasons for various crops is recommended for estimating the actual evapotranspiration at the field level.